A fan and a ventilation group comprising the fan

ABSTRACT

An axial fan has an axis of rotation and includes a hub including a bottom wall and a lateral wall extending from the bottom wall and having a peripheral edge on an opposite side with respect to the bottom wall along the axis of rotation; the fan includes a plurality of blades extending from the lateral wall externally of the hub and at least a fin internally of the hub and including an end portion projecting axially beyond the bottom wall and the lateral wall forming a cup-shaped structure of the hub, the fan including an end portion projecting axially beyond the peripheral edge externally of the hub.

TECHNICAL FIELD

This invention relates to a fan and a ventilation unit comprising a fanand a corresponding shroud.

BACKGROUND ART

The ventilation groups referred to in this specification are thosegenerally formed by a fan and a support shroud of the fan, for coolingradiators in automotive applications.

The fan is usually constituted by an electric motor, preferably of theclosed type, for actuating a corresponding fan, of the axial type in thepresent case.

The electric motor has a casing, a cap for closing the casing and anoutlet shaft which is solidly constrained to the fan by means of acup-shaped hub which at least partly houses the motor itself and fromwhich a plurality of blades project.

The shroud is provided for supporting the motor by means of acorresponding support ring and for at least partly housing the fan insuch a way as to optimise heat removal from the radiator.

The shrouds, in particular, generally comprise an external tubularmember, having a substantially cylindrical end wall, to which thesupport ring is connected by means of a plurality of arms or spokeswhich project from the cylindrical wall internally of the tubularelement.

The support ring is coaxial with the cylindrical wall and the motor ismounted coaxially with the support ring.

The prior art solutions have some drawbacks.

The positioning and fixing of the fan in the shroud do not enableeffective removal and evacuation of the heat generated by the electricmotor in operation, i.e. an adequate cooling of the cap and the casingis not enabled.

In general, the ring of the shroud for supporting the motor surroundsthe motor itself and does not allow the circulation of an air flowsuitable carrying of the heat generated in use.

The hub of the fan is in general very closed on the motor and alsoprevents a circulation of air which cools down the casing and the cap ofthe electric motor by convection.

Failure to cool the motor limits the operating temperature and thereforethe performance.

If, on the other hand, particular levels of performance are required,the duration over time of the motor is limited, should it not beproperly cooled.

In this context, the main aim of this invention is to obviate theabove-mentioned drawbacks.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to provide a fan which contributesto generating a flow of air for cooling the electric motor, inparticular both the cap and the casing.

Another aim of the invention is to disclose a ventilation group whichallows a better passage of air around the cap and the casing of theelectric motor than the prior art solutions.

The stated technical purpose and aims of the invention are substantiallyachieved by a fan according to claim 1 and a ventilation group accordingto claim 10.

BRIEF DESCRIPTION OF DRAWINGS

Further characteristics and advantages of the invention will become moreapparent from the non-limiting description that follows of a preferredbut non-limiting embodiment of a ventilation group as illustrated in theaccompanying drawings, in which:

FIG. 1 is a ventilation group according to the invention, in a schematicperspective view;

FIG. 2 is the ventilation group of FIG. 1 in a second schematicperspective view;

FIG. 3 illustrates the ventilation group of the preceding figures in aschematic perspective partly exploded view, with some parts removed forgreater clarity;

FIG. 4 is the ventilation group of the present invention in a schematicsection view with some parts removed for better clarity.

With particular reference to FIGS. 1 and 2, reference numeral 1 denotesa ventilation group according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The ventilation group 1 is preferably destined for automotiveapplications in the sector of radiator cooling.

The ventilation group 1 comprises a fan 2 having an axis R of rotationand a support shroud 3 of the fan 2.

The fan 2 comprises an electric motor 4 and a fan 5 having axial flow,or simply an axial fan, actuated by the motor 2, rotatable about theaxis R of rotation.

As illustrated in particular in FIG. 3, the motor 4, preferably of theclosed and sealed type, substantially of known type and described onlyregarding the parts necessary for understanding the present invention,comprises an external casing 6, a cap 7 for closing the casing and ashaft 8, coaxial with the axis R, to which the fan 5 is connected.

In particular, the shaft 8 comprises an end portion 9 protruding fromthe casing 6 on the opposite side with respect to the cap 7 to which thefan 5 is connected, for example by interference fitting.

The shroud 3 comprises a ring 10 for supporting the motor 4, to whichthe motor 4 is fixed in the substantially known way, for example, bymeans of screws in suitable protrusions extending from the ring 10.

The motor 4 is inserted internally of the fixed ring 10 and is supportedthereby.

The ring 10 has a external annular wall 11 from which project, on theside opposite the motor, a plurality of arms or spokes 12 ofsubstantially known type.

The wall annular 11 advantageously projects axially up to the cap 7 onthe opposite side to the fan 5.

The wall 11 preferably, has radial dimensions equal to the radialdimensions of the hub 14.

The shroud 3 comprises a tubular element 13 external of the ring 10 andto which the arms 12 are connected.

In general the ventilation group 1 is installed in a genericapplication, which is not illustrated, by means of the element tubular13 which in turn, by means of the arms 12 and the ring 10, supports thefan 2.

Observing the fan 5 in more detail, it should be noted that it comprisesa cup-shaped hub 14 and a plurality of blades 15 extending from the hub14 and preferably made in a single body with the hub by moulding using aplastic material.

As illustrated in FIG. 4, the motor 4 is housed at least partlyinternally of the hub 14.

The hub 14 comprises an end wall 16 by means of which the fan 5 isconnected to the shaft 8.

The hub 14 comprises a lateral wall 17 extending from the end wall 16and having a peripheral edge 18, substantially circular in shape, on theside opposite the end wall 16 along the axis R of rotation.

The end wall 16 and the lateral wall 17 define a cup-shaped structurefor the hub 14.

The blades 15 extend preferably from the lateral wall 17 of the hub 14towards the outside thereof, externally of the cup-shaped structure.

With reference in particular to FIGS. 3 and 4, it can be observed thatthe fan 5 comprises a plurality of fins 19, preferably made in a singlebody with the hub 14, internal of the cup-shaped structure forgenerating, in use, a descending flow of tangential air internally ofthe hub 14 for removing heat from the motor 4.

In the illustrated preferred embodiment, the fins 19 are angularlyequi-spaced internally of the hub 14 and are for example seven innumber.

Each fin 19 comprises a portion 20 projecting beyond the peripheral edge18 of the lateral wall 17, externally of the cup-shaped structure, i.e.outside the hub 14.

Preferably, the end portions 20 protrude externally of the hub 14 alongan axial direction, substantially parallel with the axis R of rotationof the fan 2.

In the illustrated preferred embodiment, each appendage 19 has a firstportion 21 extending from lateral wall 17 internally of the hub 14,preferably radially.

The first portion 21 has main extension direction that is parallel tothe axis R of rotation of the fan 5 and preferably extends along theentire axial dimension of the hub 14 towards the inside of the hub 14.

The end portions 20 are preferably defined by an at least partialextension of the first portion 21 beyond the edge 18.

In the preferred embodiment illustrated, each fin 19 comprises a secondportion 22 extending from the end wall 16 towards the inside of the hub14.

Each second portion 22 is connected and extends into a correspondingfirst portion 21.

Each second portion 22 preferably has a main extension direction that issubstantially radial and extends towards the inside of the hub 14.

With reference in particular to FIG. 4 it may be observed that the fins19 are substantially L-shaped, with the second radial portion 22 and thefirst axial portion 21 located inside the hub 14 and the end portion 20exiting therefrom.

Each end portion 20 has an internal edge 23 facing internally of the hub14, i.e., towards the electric motor 4, and an external edge 24 facingexternally of the hub 14, i.e. towards the blades 15.

In the illustrated preferred embodiment, the external edge 24 is at aradial distance from the axis R of rotation that is less than a radialdistance of the lateral wall 17 from the axis R of rotation.

In practice, each portion 20 is slimmed in a radial direction relativeto the corresponding first portion 21 of the respective fin 19.

To facilitate outflow of the air moved by the fins 19 in use, the hub 14has a plurality of through-holes 25 at a connecting zone 26 of the endwall 16 and the lateral wall 17.

The connecting zone 26 preferably has a curved extension and the holes25 preferably have rounded edges.

The heat removed from the casing and the cap, in a flow having aprevalently axial component, advantageously flows out from the hub 14through the holes 25.

With reference in particular to FIG. 4, it can be observed that theannular wall 11 delimits, with the external surface of the electricmotor 4, an annular channel 27.

The end portions 20 of the fins 19 are preferably at least partlyinserted internally of the channel 27.

More precisely, the portions 20 are slimmed as described in theforegoing so as to be inserted internally of the channel 27.

The lateral wall 11 of the ring 10 preferably has a radial dimensionsubstantially corresponding to the radial dimension of the hub 14 and inparticular of the lateral wall 17 thereof. More precisely, asubstantially cylindrical internal surface of the wall 11 has the sameinternal diameter as the lateral wall 17 of the hub 14.

In this way, a descending flow of tangential air is guided about thecasing 6 and the cap 7 of the motor so as to carry heat away from both.

In particular, a component of the tangential flow for cooling the cap isdetermined by the portions 20 of the fins which extend outside the hubinternally of the annular channel 27.

1. An axial fan having an axis of rotation and comprising a hubcomprising a bottom wall and a lateral wall extending from the bottomwall and having a peripheral edge on an opposite side with respect tothe bottom wall along the axis of rotation, the bottom wall and thelateral wall forming a cup-shaped structure of the hub, the fancomprising a plurality of blades extending from the lateral wallexternally of the cup-shaped structure; at least a fin internal of thecup-shaped structure for generating, in use, a tangential flow of airinternally of the hub, the fan being characterised in that the fincomprises an end portion projecting beyond the peripheral edgeexternally of the hub.
 2. The fan according to claim 1 wherein the finhas a first portion extending from the lateral wall towards the insideof the hub, the end portion being defined by an at least partialextension of the first portion.
 3. The fan according to claim 2 whereinthe first portion is parallel to the axis of rotation.
 4. The fanaccording to claim 1 wherein the fin comprises a second portionextending from the bottom wall towards the inside of the hub.
 5. The fanaccording to claim 4 wherein the second portion extends radially fromthe axis of rotation.
 6. The fan according to claim 1, wherein the endportion extends mainly parallel to the axis of rotation.
 7. The fanaccording to claim 1, wherein the hub has a plurality of through-holesat a zone connecting the bottom wall and the lateral wall.
 8. The fanaccording to claim 1, wherein the end portion has an internal edgefacing internally of the hub and an external edge, facing externally ofthe hub, the external edge being positioned at a radial distance fromthe from the axis of rotation that is less than a radial distance of thelateral wall from the axis of rotation.
 9. The fan according to claim 1,wherein the hub, the blades and the fin are made in a single part bymoulding.
 10. A ventilation group comprising a fan and a support shroudof the fan, the fan comprising an electric motor and a fan actuated bythe electric motor the electric motor comprising a casing, a cap forclosing the casing and a shaft to which the fan is connected, the shroudcomprising a support ring of the electric motor having an externalannular wall, the ventilation group being wherein the fan is of the typeaccording to claim 1 and the electric motor is at least partly housedinternally of the hub.
 11. The ventilation group according to claim 10wherein the external annular wall delimits, with the electric motor, anannular channel, the end portion of the fin being at least partlyinserted in the annular channel.
 12. A ventilation group according toclaim 10, wherein the shaft comprises an end portion, protruding fromthe casing on the opposite side from the cap, to which the hub of thefan is connected, the external annular wall extending axially up to thecap on the opposite side with respect to the fan.
 13. The ventilationgroup according to claim 10 wherein the external annular wall has aradial dimension that is equal to the radial dimension of the hub.